Cao Huan, Si Yichuan, Chen Yihui, Liang Quanbin, Wu Hongbin
Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
ACS Appl Mater Interfaces. 2022 Aug 3;14(30):34926-34936. doi: 10.1021/acsami.2c07924. Epub 2022 Jul 22.
Selective spectral response photodetectors (PDs) capable of accurately capturing the color of images have broad applications in industry and academia. Here, we demonstrate filter-free, wavelength-selective detection organic photodetectors (OPDs) with two distinct response ranges and having the planar bilayer heterojunction device structure by employing either a (semi-)transparent anode or a cathode as the incident light window. The resultant OPDs exhibit a responsivity of 51 mA W in the range 300-650 nm and 11 mA W in the range 650-850 nm under top illumination condition. Similarly, the devices show a responsivity of 2 mA W for the short-wavelength region and 131 mA W for the long-wavelength region when under bottom illumination condition, indicating a high responsivity ratio that meets the requirements for selective detection. Hence, our individual device not only works in either visible or NIR range but also provides narrowband detection with spectral widths down to 100 nm in the NIR range. The working mechanism of spectral selectivity is identified through quantitative analysis of the external quantum efficiency (EQE) spectra using optical modeling when compared to the OPDs with bulk heterojunction structure, thus clarifying the general validity of the device design concept. Finally, our OPDs can demultiplex intermixed optical signals from the light-communication system successfully. Our results should inspire new studies on the device design concept and new applications of OPDs.
能够精确捕捉图像颜色的选择性光谱响应光电探测器（PDs）在工业和学术界有着广泛的应用。在此，我们展示了无滤光片、波长选择性检测的有机光电探测器（OPDs），其具有两个不同的响应范围，并通过采用（半）透明阳极或阴极作为入射光窗口，具备平面双层异质结器件结构。在顶部照明条件下，所得的OPDs在300 - 650 nm范围内的响应度为51 mA/W，在650 - 850 nm范围内为11 mA/W。同样，在底部照明条件下，器件在短波长区域的响应度为2 mA/W，在长波长区域为131 mA/W，表明其具有满足选择性检测要求的高响应度比。因此，我们的单个器件不仅能在可见光或近红外范围内工作，还能在近红外范围内提供光谱宽度低至100 nm的窄带检测。通过与具有体异质结结构的OPDs相比，利用光学建模对外部量子效率（EQE）光谱进行定量分析，确定了光谱选择性的工作机制，从而阐明了器件设计概念的普遍有效性。最后，我们的OPDs能够成功地对来自光通信系统的混合光信号进行解复用。我们的结果应能激发关于器件设计概念的新研究以及OPDs的新应用。
